1. Field of the Invention
This invention relates to a keyboard assembly for use in an electronic organ and the like.
2. Prior Art
In general, a conventional keyboard assembly having white keys and black keys juxtaposed to each other is constructed such that white key units and black key units are each formed of bodies of white or black keys connected to a key support member via respective connecting portions (hinges) in a manner being swingable in directions of key depression and release, with a white key unit and a black key unit of each pair being laminated one upon the other at the key support member and being fixed to a main frame or the like. Further, except for a miniature type keyboard assembly having short key bodies, the keyboard assembly has a key guide provided in the vicinity of a front end (free end) of each key to increase the flexural rigidity of the key for limiting motions of the key body in lateral directions in which the keys are juxtaposed (lateral motions) to thereby limit lateral motions of keys and hence facilite and improve the performance of glissando etc.
The provision of the key guide, however, complicates the construction of the keyboard assembly and is hence disadvantageous in respect of the manufacturing cost. Further, it requires applying grease to portions of the body of each key in sliding contact with the key guide for prevention of mechanical noise. This is not only troublesome but also undesirable from the view point of the quality of performance played by the keyboard assembly since the mechanical noise is generated when the grease becomes short. Further, when a foreign substance, such as dust, is caught between the body of a key and the key guide, this impedes smooth key-depressing operation.
To solve the above-mentioned problems, a key board assembly has been proposed by Japanese Laid-Open Patent Publication (Kokai) No. 7-92963, in which the connecting portion of each key is made larger in lateral width than a rear end portion of the key body and at the same time disposed to partially overlap with the connecting portions of adjacent keys. This can fully limit lateral motions of keys even without the use of the key guide.
The proposed keyboard assembly which thus does not employ the key guide, however, requires increasing the lateral width of the connecting portion of each key to such a degree that the connecting portion becomes much wider than the width of the key body so as to increase the flexural rigidity of the key in the lateral directions. In other words, to avoid interference between adjacent connecting portions, it is required to group white keys into a plurality of divisional units (e.g. upper and lower units) even over a range of one octave of musical tones. This makes it impossible to form the white keys into a single unit in which they are arranged in the order of pitch and connected to the key support. As a result, the construction of the keyboard assembly is complicated, and it is troublesome to adjust the divisional units for alignment, which results in an increased manufacturing cost.